OSTEOGENIC FACTOR FROM DENTIN MATRIX

牙本质细胞外基质含有一种蛋白质因子， 调节培养的成纤维细胞的表型表达的能力， 转化成软骨细胞的产物。 的 牙本质基质具有BMP样活性。 也就是说，牙本质基质植入物 在植入物模型上诱导骨形成， 一种完全类似于BMP活性骨基质的方式。 在 上一个项目期间，牙本质体外软骨形成因子（CIA）是 纯化并部分表征。 中央情报局的组成是不同的 与骨BMP和TGF-β超家族的其他成员不同。 的 CIA作为6000先生单体是活跃的，不受减少的影响， 不含TGF-β共同的C-末端富含Cys的区域 超家族 N-末端测序已经导致制备 核苷酸探针和检测推定的CIA克隆， 测序 原位杂交研究已经开始定位 中情局的mRNA 延续期的具体目标是： 1)在序列和基因结构方面充分表征CIA; 2） 生产可操作数量的重组CIA，并使用该蛋白质 在体外检查CIA的作用机制;和，3）确定在体外的CIA的作用机制。 CIA+载体植入物的体内活性。 在目标2中， 胶原蛋白和蛋白多糖产生的表型变化， 细胞表面受体的性质和数量，以及细胞表面受体的诱导， 调节蛋白将在大鼠肌肉成纤维细胞中进行研究， 确定的非成骨细胞系C3 H10 T1/2。cDNA差异文库将是 准备和筛选。 一个重要的新发展是， 在培养物中诱导致密软骨样结节。 这些结节可以 植入体内，并将作为替代方案进行研究 骨/软骨诱导修复系统。 除了他们内在的 有趣的是，这3条调查线应该会导致更好的 了解细胞分化的调节过程中正常的 发育以及硬组织的修复。

The dentin extracellular matrix contains a protein factor which has the ability to modulate the phenotypic expression of cultured fibroblasts, and switch them to produce products characteristic of chondrocytes. The dentin matrix has a BMP-like activity. That is, a dentin matrix implant into muscle in vivo induces bone formation on the model of the implant in a fashion entirely analogous to BMP-competent bone matrix. In the previous project period the dentin in vitro chondrogenic factor (CIA) was purified and partially characterized. The CIA composition was distinct from that of bone BMP and other members of the TGF-beta superfamily. The CIA was active as a Mr 6000 monomer, was unaffected by reduction, and did not contain the C-terminal Cys-rich region common to the TGF-beta superfamily. N-Terminal sequencing has led to the preparation of nucleotide probes and detection of putative CIA-clones which have been sequenced. In situ hybridization studies have been initiated to localize the CIA mRNA. The specific objectives of the continuation period are to: 1) fully characterize the CIA in terms of sequence and gene structure; 2) produce workable quantities of recombinant CIA and use the protein to examine in vitro the mechanism of CIA action;, and, 3) determine the in vivo activity of CIA+ carrier implants. In Objective 2, the nature of the phenotypic changes in collagen and proteoglycan production, the nature and number of cell surface receptors, and the induction of cell regulatory proteins will be studied in rat muscle fibroblasts and in the defined nonosteogenic line, C3Hl0T1/2. cDNA difference libraries will be prepared and screened. An important new development has been the induction of dense cartilage-like nodules in culture. These nodules can be implanted in vivo and will be investigated as an alternate bone/cartilage inductive repair system. Aside from their intrinsic interest, these 3 lines of investigation should lead to a better understanding of the regulation of cell differentiation during normal development as well as to the repair of hard-tissues.